The "big screen" controls the whole car! Just b/c the google maps is gone doesn't mean you will stop using it!!! And I much prefer the navigation directions popping up in easy view on the gauge than almost every other car out there where you have to look at the screen in the center console!
Personally I think everyone is doing waaaaay too much bitching about this! If you don't want to spend $30/month....DON'T! I'm not going too!
Use Bluetooth streaming and player slacker, or tunein, or pandora, (or your own music library) from your phone.
As far as navigation...the Navigon is fine! It's turn by turn directions and (again) you have your phone to check traffic on google maps. Or use WAZE app which uses social crowding to give you the most up to date traffic info. (Actually better than googles traffic reporting if you would believe it!!!).
Also the tech package included loads of other stuff...not just the navi.
I hope they either allow tethering...or someone figures out how to hack it....since that would solve the problem for most people. If they announce tethering I think people would stop bitching (and then the "oh joy!!!" Posts will start!).